Department of Medical Sciences, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, via Fossato di Mortara 70, 44121 Ferrara, Italy; Department of Biochemical Sciences, University Sapienza, P.le Aldo Moro 5, 00185 Rome, Italy; Department of Chemistry - BMC, Uppsala University, Husargatan 3, 751 23 Uppsala, Sweden.
Department of Pharmaceutical Sciences, University of Perugia, Via Fabretti 48, 06123 Perugia, Italy.
Biochim Biophys Acta Gen Subj. 2020 Aug;1864(8):129618. doi: 10.1016/j.bbagen.2020.129618. Epub 2020 Apr 17.
Sorcin is a calcium sensor that exerts many calcium-related functions in the cells, e.g. it regulates calcium concentration in the cytoplasm, endoplasmic reticulum (ER) and mitochondria, by interacting with calcium pumps, exchangers and channels. Albeit Sorcin is an interesting potential cancer target, little is known about its interactors upon calcium-mediated activation. Our previous study suggested that Sorcin may recognize short linear binding motifs as the crystal structure revealed a self-interaction with a GYYPGG stretch in its N-terminus, and combinatorial peptide-phage display provided support for peptide-mediated interactions.
In this study we screened for motif-based interactions between Sorcin and intrinsically disordered regions of the human proteome using proteomic peptide phage display (ProP-PD). We identified a peptide belonging to protein phosphatase 1 regulatory subunit 3G (PPP1R3G) as a potential novel interactor and confirm the interaction through biophysical and cell-based approaches, and provide structural information through molecular dynamics simulations.
Altogether, we identify a preferred motif in the enriched pool of binders and a peptide belonging to protein phosphatase 1 regulatory subunit 3G (PPP1R3G) as a preferred ligand.
Through this study we gain information on a new Sorcin binding partner and profile Sorcin's motif-based interaction.
The interaction between Sorcin and PPP1R3G may suggest a close dependence between glucose homeostasis and calcium concentration in the different cell compartments, opening a completely new and interesting scenery yet to be fully disclosed.
Sorcin 是一种钙传感器，它通过与钙泵、交换器和通道相互作用，在细胞中发挥许多与钙相关的功能，例如调节细胞质、内质网 (ER) 和线粒体中的钙浓度。尽管 Sorcin 是一个有趣的潜在癌症靶点，但关于其在钙介导激活时的相互作用物知之甚少。我们之前的研究表明，Sorcin 可能识别短线性结合基序，因为晶体结构显示其 N 端的 GYYPGG 延伸段存在自身相互作用，组合肽噬菌体展示为肽介导的相互作用提供了支持。
在这项研究中，我们使用蛋白质组肽噬菌体展示（ProP-PD）筛选 Sorcin 与人类蛋白质组中固有无序区域之间基于基序的相互作用。我们鉴定了一个属于蛋白磷酸酶 1 调节亚基 3G（PPP1R3G）的肽段作为一个潜在的新相互作用物，并通过生物物理和基于细胞的方法验证了相互作用，通过分子动力学模拟提供了结构信息。
总之，我们确定了在富集的结合物池中存在一个首选基序和一个属于蛋白磷酸酶 1 调节亚基 3G（PPP1R3G）的肽段作为首选配体。
通过这项研究，我们获得了关于 Sorcin 新结合伙伴的信息，并分析了 Sorcin 基于基序的相互作用。
Sorcin 与 PPP1R3G 之间的相互作用可能表明葡萄糖稳态和不同细胞区室中钙浓度之间存在密切的依赖关系，开辟了一个全新的、有趣的领域，有待进一步揭示。
